Leucocoprinus ianthinus

Leucocoprinus ianthinus is a species of mushroom producing fungus in the family Agaricaceae. Like several other Leucocoprinus species it may have originated in a tropical climate but now finds a home in plant pots, greenhouses and compost piles in many countries. It is not seen in plant pots with the same kind of regularity as the well known Leucocoprinus birnbaumii and not seen in the wild as frequently as Leucocoprinus brebissonii....read more on Wikipedia.